If your tiles sound hollow and 'drummy' when tapped on, there is an installation issue. It may be that there is nothing to worry about, especially if they have always sounded that way. If it is a new situation that arises, however, and areas of wall tiles start to sound drummy; then it is a symptom of a more serious problem.
A drummy tile installation is simply the result of incorrect tiling.
• If the tiler 'dobs' the adhesive on the tiles, he will not achieve 100% coverage on the back of the tile. The hollow void behind the tile will sound drummy.
• If the tiler lays the tiles in very hot conditions, or simply leaves the adhesive on the wall for too long before applying the tile, the adhesive will start to cure. This is called skinning, as the surface dries as it loses its tackiness and adhesion. This will cause a drummy sound if knocked because, again, there is not 100% adhesion to the tile.
• Excess water penetrating behind the tile can break down some tile adhesives. This will result in failure of the adhesive if this occurs for a prolonged period of time. The first indication of this will be the drummy sound of the tiles.
• If your tiles have been adhered to an inappropriate waterproofing product, you can expect tiling failure. This may be that the waterproofing material does not adhere to the substrate, or that the adhesive will not bond to the waterproofing itself.
None of the above situations are ideal, and we would always recommend that the tiling be rectified by the builder or tiler responsible. Unfortunately, the only way to fix this sort of problem is to retile the area properly. If it is due to a waterproofing failure, that will also need to be reapplied.
If the tiles sound drummy immediately following installation, however, and if only a few isolated tiles are affected; you may want to be prepared to avoid the convenience of repair work. If so, talk to your builder or tiler and ask for a signed guarantee that they will rectify the issue promptly and at no charge if the tiling system does fail at some future date.
If the installation seemed fine initially, but after some time (usually at least a year) the drumminess occurs, you need to prepare for repair work at your earliest convenience. The tiles may start to fall off the wall, but the damage to the substrate is the critical issue.
Get in touch with your builder or tiler as soon as possible.
